Press motor controls



Nov. 24, 1942. o. M. BUNDY PRESS MOTOR CONTROLS Filed Sept. 11; 1940 4Sheets-Sheet 2 lvs .7 R Y. WW W m WMKA M W O V 563 //M cam 53% m Nov.24, 1942. I QM. BuNpY 2,302,838

rns'ss MOTOR CONTROLS Filed Sept. '11, 1940 4 Sheets-Sheet a ILL?INVENTOR;

Nov. 241; 1942. o. M. BUNDY PRESS MOTOR CONTROLS Filed Sept. 11, 1940 4shuts-sheet 4 1 l IL INVENTOR. 'Qsrka/c/ 5U/7df/ .BY 7 ATTORNEY.

Patented Nov. 24, 1942 UNITED STATE-d OFFICE PRESS MOTOR CONTROLSApplication September 11, 1940, Serial No. 356,298

7 Claims.

This invention relates to electrical control systems for machinery ofthe class in which a cycle of movements is performed, for example, powerpresses in which a reciprocator or head reciprocates in one directionfrom a starting position, to perform a pressing operation on workpieces, and then is reciprocated back in the other direction to thestarting position to complete the cycle; and the invention relatesparticularly to electrical control systems for controlling the powerapplied to the machine to control the operation thereof, and to insureagainst abnormal operation such as unintended starting of the machine orunintended continued or repeat operation thereof, et cetera, whereby themachine or the work might be damaged or workmen at the machine might beinjured.

Such control systems have been proposed in which the power for themachine is supplied by a continuously running electric motor, a clutchbeing provided to transmit the motor power to the machine to start andoperate it and a brake being provided to stop the machine; and theclutch and brake have been so arranged that the brake is dis-engagedwhen the clutch is engaged and vice versa; and a control system for theclutch and brake has been provided operable by power such as pneumaticpower under the control of a plurality of operators push-buttons.

According to the present invention, the power is supplied by an electricmotor which is at all times connected directly mechanically to themachine, and the operations of the machine are effected by starting andstopping the motor, a brake being provided to bring the machine and themotor quickly to rest at the time of stopping. The clutch of priorsystems therefore is not nec essary and is eliminated. The energizationof the motor to start it, to initiate the cycle of operations of themachine, is effected through the agency of a control system utilizingmagnetic contactors and under the control of push-buttons operated bythe operators of the machine; and the control system is arranged toprovide safety features including among other things provision to insurethat the hands and arms and other parts of the operators bodies will beout of the path of moving parts of the machine before the motor can bestarted, and to insure that the operators must remain in such safetypositions until the operation of the machine has passed through enoughof the cycle to remove the liability of danger; and provision to insurethat the motor of the machine will stop automatically at the end of acycle of operation; and that after one cycle has been completed and themotor and parts have stopped, another cycle will not be automaticallyinitiated even if the operators should inadvertently hold any of thepush-buttons operated, and not until all of the pushbuttons have beenreleased and again operated.

A master selector or controller is provided which may be set to changethe operating characteristics of the control system to cause it toeffect optionally either the stopping automatically of the machine atthe end of each cycle; or continuous repeat operation of the machine,cycle after cycle, after the machine has once been started and subjectto being stopped at any time by manually operable means such as stoppush-buttons; or to effect small inching increments of movement of themotor and machine such as is usual in setting up the dies and the workin the machine preparatory to continued production use thereof; and toprovide for such inching operations, the motor and machine may beoperated in the forward or the reverse direction, as optionally desired,

The control system comprises, beside pushbuttons under the control ofthe machine operators, and besides the master selector or controller,contactors operated mechanically by the movement of an element of themachine, and electromagnetic contactors; and simplification is effectedto the end that the control of the electric power to the motor to driveit in the forward or in the reverse direction as desired, is effected byonly three motor current or main current magnetic contactors.

As stated hereinbefore, the clutch of prior systerm; is eliminated bythe present invention, and the brake for stopping the motor and themachine is operated by power under the control of an electrc-magneticdevice having an actuating winding constituting part of the controlsystem,

While the control system of the present invention compriseselectro-magnetic contactors to initiate energization of the said devicewinding and of the motor current contactors under the control of manualpush-buttons or like contactors, the breaking of the control currentthereto may be effected directly by the push-buttons upon opening themwhereby accidental sticking closed of any electro-magnetic contactor,which may occur in practice, cannot result in accidental or unexpectedabnormal operation of the system and the machine, with the attendantdangers thereof, when the push-buttons are opened with intention ofstopping the machine.

The present invention has perhaps its most important application topower operated presses of the vertically reciprocatory type and willtherefore be illustrated and described as applied to that use, althoughas will become apparent hereinafter my invention is not limited in itsapplication to presses, but may be applied generally to machinery whichhas a cycle of operations.

It is among the objects of this invention:

To provide generally an improved control systern for cyclicallyoperating machines of the type in which an electric motor supplyingpower to the machine is mechanically connected thereto at all times;

To provide generally an improved control system for cyclically operatingmachines of the class referred to having provision to insure that themachine will not accidentally start or accidentally continue to run whennot intended;

To provide a control system for cyclically operating machines of thetype referred to in which the energization of the motor to start it iscontrolled by a plurality of operators push-buttons and having improvedmeans for causing the machine and the motor to positively stop uponrelease of any one of the push-buttons;

To provide a control system for cyclically operating machines of theclass referred to employing an electro-magnetically controlled brake tostop the machine and motor, and having improved means for insuring thatthe brake will be released before electric power is given to the motorto start it;

To provide in a control system for cyclically operating machines of theclass referred to in which the control of power to drive the machine iseffected by a system actuated upon closing operators push-buttons,improved means Whereby the motor will be de-energized and stopped uponthe release of any push-button;

To provide a control system for the motor of a cyclically operatingmachine by which among other features the motor and the machine may bestarted only after all of the operators pushbuttons are closed; and willstop if any pushbutton is released and unless the push-buttons are heldclosed for a predetermined part of the operating cycle of the machine;and which will continue to run to the end of the cycle after thepush-buttons have been released; and which will automatically stop atthe end of the cycle; and in which the portion of the operating cyclethrough which the push-buttons must be held closed may be adjustablyvaried in an improved manner; and in which the machine will stopautomatically at the end of the cycle in the event of voltage failure orin the event that the pushbuttons are held operated and not released atall; and which cannot be started to begin a cycle unless all of thepush-buttons have been released;

To provide generally an electric control system i or machines of thecyclically operating type having improved means for insuring safety ofoperation thereof by preventing accidental operation thereof withconsequent liability of damage to the machine or to the work or toworkmen who may be operating the same;

To provide in a control system of the type referred to comprising anelectro-magnetic brake, and an electro-magnetic device controlling itand in turn controlled by a push-button, im-

proved means whereby the energization of the device may be effectedafter closure of the pushbutton but de-energization thereof may beeffected directly at the push-button upon opening it.

Other objects will be apparent to those skilled in the art to which myinvention appertains.

My invention is fully disclosed in the following description taken inconnection with the accompanying drawings in which Fig. l is a, frontelevational view in some respects diagrammatic of a power operated pressto the control of which my invention is particularly applicable, andillustrating in connection therewith a brake and an electro-magneticallyoperable valve device for controlling fluid pressure to operate thesame, and illustrating also diagrammatically a number of limit switchesoperated by movement of the main shaft of the press;

Fig. 2 is a view taken generally from the plane 2--2 of Fig. 1, andillustrating in side elevation and somewhat diagrammaticaly one of thelimit switches of Fig. l, with means for adjusting the operationthereof;

Fig. 3 is a diagrammatic view illustrating the preferred control systemfor the machine of Fig. l and embodying my invention;

Fig. 4 is a diagrammatic view of a master controller or selector whichmay be used with the system of Fig. 3;

Fig. 5 is a view similar to Fig. 3, but illustrating a modification;

Fig. 6 is a diagrammatic view illustrating the power circuit to anelectric motor shown in Fig. 1;

Fig. '7 is a view illustrating the timed sequence of operation ofcertain limit switches of Fig. 3.

Referring to the drawings, Figs. 1 and 2, I have shown generally at lthe main base of a poweroperated press having a crank shaft 2 and a pairof cranks 3-3 which operate connecting rods 4-4 to reciprocate an upperhead 5 toward and from a static-nary head 6 to perform pressingoperations upon work-pieces placed in dies or the like (not shown), butto be as usual mounted on the heads 5 and 6.

A revolution of the shaft 2 and a complete alternate reciprocation ofthe head 5 constitutes a cycle of operations of the machine, and theparts are illustrated in Fig. 1 at the beginning of the cycle.

Mounted adjacent to the machine or upon it is a plurality of operatorspush-buttons 1-1. Preferably two push-buttons are provided for eachoperator of the machine and usually a number of pairs of suchpush-buttons will be provided, although only one pair has been shown,and the control system to be described is ar ranged so that all of theoperators push-buttons must be closed before the head 5 will startdownwardly whereby the operators hands and arms and other parts of hisbody will be out of the line of movement of the head 5, and thereforeout of danger of injury thereby, and to this end the push-buttons |l maybe disposed at some distance from the head 5.

A gear 8 is mounted on the shaft 2 and is meshed with a motor pinion 9on the shaft of an electric motor [0 supported on the frame I or upon abracket H thereof.

The end of the shaft 2 projects outwardly beyond the gear 8 and issplined as shown at [2 and meshed with the splines is the hub l3 of abrake actuator having a brake ring 14 normally engaged with a brake ringl5 mounted on a bracket [8 on the machine frame. The actuator has a ballrace I! diagrammatically shown to be in the form of a disc within ahousing [8 in which are mounted ball bearings 19 and 20 on oppositesides of the race IT; and the housing [8 is connected to the piston rod2| of a piston 22 reciprocable in a cylinder 23; and the piston 22 isnormally held toward the right, as viewed in the drawing, by a spring24; and the thrust of the spring is transmitted through the piston 22and housing I8, and thence through the ball bearing 19 to the disc I1,and to the actuator I3, and thereby holds the brake ring I4 inengagement with the brake ring I5, and acting through the splines I2exerts a braking action on the shaft 2 to hold it from rotation or tostop it if it is rotating.

When the piston 22 is reciprocated toward the left, as viewed in thedrawing, against the tension of the spring 24, the actuator I3 is movedby the ball bearing 20 toward the left on the splines I2 and dis-engagesthe brake rings I4 and I5 to free the shaft so that the motor I mayfreely drive the press when energized.

The piston 22 is operated by air pressure from a source 25 controlled bya valve device shown generally at 26. In the normal position of theparts illustrated, the cylinder 23 is exhausted through a conduit 21 toa chamber 28, through a valve port 29 to a chamber 30 and out toatmosphere at 3|, and the air pressure from the source 25 is cut off ata port 32 by a valve 33 held in port-closing position by a spring 34.

An electro-magnetic winding 35 is provided which, when energized, movesa plunger 33 to compress the spring 34 and retract the valve 33 touncover the port 32 and close the port 29, whereupon air pressure fromthe source 25 flows by a conduit 31 through the port 32 to the chamber28, and by the conduit 21. to the cylinder 23 to move the piston 22against the tension of the spring 24 for the purpose of releasing thebrake as described.

From the foregoing description, it will now be apparent that when theelectro-magnetic winding 35 of the valve device 26 is energized thebrake of the machine is released and that when the winding 35 isde-energized the brake is set by the spring 24; and that energization ofthe winding 35 may be effected by an electric circuit comprising wires38 and 39.

The left-hand end of the shaft 2, as viewed in Fig. 1, extends beyondthe machine and has mounted thereon a plurality of cam-operated limitswitches 40 and M, the general location of these being indicateddiagrammatically in Fig. l, and the construction of one of them beingillustrated in Fig. 2.

Any desired number of such limit switches may be employed, two beingshown in Fig. 1 and. six being shown in the control system of Fig. 3.

Upon the shaft 2, Fig. 2, is mounted by means of a screw 42, a cam 43having a cam surface 44, preferably in two overlapping parts, a frontpart 45 and a rear part 45 having arcuate slots 41 and 48 thereinrespectively, through which a clamp bolt 49 is projected to lock themtogether. The part 45 is secured upon the shaft 2 by the screw 42, butmay be adjustably positioned around the shaft by loosening the screw andshifting the part and again tightening the screw, and the part 46 may beshifted around the shaft and then socured to the part 45 by the bolt 49whereby the extent of the cam surface 44 may be adjustably varied aswell as its angular position around the shaft 2.

A contactor arm 53 is pivotally mounted on a suitable support I, notshown in Fig. 1, and has a finger 52 engaged with the cam surface '44 bya spring 53 and the arm 53 carries a movable contact 54 opposite astationary contact 55.

As will be apparent from this diagrammatic construction, when the shaft2 is rotated, the cam surface 44 will leavethe finger 52 and the spring53 will close the contacts 54 and 55 and as the shaft continues torotate the finger 52 will ride up on the cam surface 44 and disengagethe contacts 54-55.

Obviously the cam switch of Fig. 2 may, when the shaft 2 is at thebeginning of its cycle, be positioned either to cause the contacts 5455to be engaged or dis-engaged.

Referring now to Figs. 3 and 4 which illustrate the control systemembodying my invention in its preferred form, siX of these cam-operatedlimit switches have been reproduced diagrammatically as follows:switches 56, 51 and 58 normally closed and switches 59, 60 and GInormally open; and in Fig. 3 is reproduced the valve winding 35 and itsplunger 36 and the circuit wires 33 and 39 thereof as well as thepush-buttons 'I-'I, four of the same being shown.

Besides the parts referred to above there is in Fig. 3 a magneticcontactor shown generally at A having four sets of normally opencontacts Al, A2, A3, A4; and a magnetic contactor B having there sets ofnormally open contacts BI, B2, B3; and. a magnetic contactor C havingfour sets of normally open contacts CI, C2, C3, C4, and a set ofnormally closed contacts C5; and a magnetic contactor D having four setsof normally open contacts, DI, D2, D3, D4; and a magnetic contactor Fhaving a normally closed set of control contacts FI, and a normally openset of control contacts F2, and two sets of normally open main motorcurrent contacts, F3 and F4; and a magnetic contactor M having a set ofnormally open control contacts MI and a pair of normally open main motorcurrent contacts M2 and M3; and a magnetic contactor R, having a set ofnormally closed control contact-s RI, and a set of normally open controlcontacts R2, and a pair of normally open main motor current contacts R3and R4; and a magnetic contactor G having a set of normally closedcontacts GI, and two sets of normally closed contacts G2 and G3; and amagnetic contactor H having four sets of normally open contacts HI, H2,H3, H4.

To simplify the circuits of the system of Fig. 3, the control contactsof the switches A, B, C, D, F, M, R, G, H, are reproduced elsewhere inFig. 3; and the main motor current contacts of the contactors F, M and Rare reproduced in Fig. 6, in connection with the motor which theycontrol.

The master controller or selector, Fig. 4, when operated as will bedescribed, closes pairs of contacts and these pairs of contacts 62-63 to'I4I5 inclusive, in pairs, are also reproduced in Fig. 3.

The operators push-buttons 'I'II'I each control normally closed contacts'I6'I6 and normally open contacts 'II'II. An inching control push-buttonI8 for effecting inching movements of the motor and the machine in theforward direction controls normally closed contacts I9 and and normallyopen contacts BI and 82; and an inching push-button 83 for controllinginching moving in the reverse direction controls normally closedcontacts 84 and 85 and normally open contacts 86 and 81. A stoppush-button is shown at 88 and any number of such stoppush-buttons inseries may be provided.

The master controller or selector of Fig. 4 is provided to determinewhether the system is to be operative or not; and whether the press isto run a single cycle and then stop; or whether it is to runcontinuously, cycle after cycle, after heing once started until stopped;or whether it is to be inched ahead by small increments of movement suchas are necessary to adjust the work and the dies on the heads 5 and 6 ofthe machine; and these positions are designated in Fig. 4, by thelegends Off, Run, Continuous, and Inch, and the controller beingillustrated in the Off position.

The various connections in the system will now be described inconnection with a description of its operation as a whole.

Assuming that it be desired to operate the machine to run by singlecycles, the controller of Fig. 4 is moved to engage the contacts of theoff position with those of the run position, thereby connecting contacts62 53 and E i-65, Fig. 4 and Fig. 3. In Fig. 3, current thereupon flowsfrom the main 89 through the contacts of the push-button I23, contacts623 to wire 93, through the contacts I6 of two of the push-buttons I,through the winding 04 of the contactor A, through the contacts 76 ofthe other two pushbuttons to a wire 95, through the contacts 64-85 tothe main 90.

Contactor A is thereby operated closing its contacts Al to A4.

A maintaining circuit is thereby made for the contactor A from the wire93, through the closed limit switch 56, through now closed contacts A5,through the winding 94, through now closed contacts A2, through thelimit switch 51, through the wire 95 and so on, thereby bridging thecontacts I6 of the push-buttons l1, so that the contactor A will remainoperated when the push-buttons 'I'l are presently depressed to open thecontacts 16.

To start the motor I to start the press and initiate its cycle, thepush-buttons 'I-'I are depressed opening the contacts 16 and closing thecontacts I? thereof, and thereupon the winding 96 of the contactor B isenergized, the current flowing as before to the wire 93, thence throughthe contacts TI of the first two push-buttons, through noW closedcontacts A3 to a wire 91, through closed limit switch 56, through thewinding 90, to a wire 98 thence through closed contacts A4, and throughthe other contacts II of the other push-buttons to wire 05, and so on,closing the contacts BI to B of the contactor B.

The operation of the contactor B effects energization of the windings S9and I00 of contactors C and D, the current which flowed to the wire 9'!flowing through closed contacts BI, to a wire IOI and by wire I62through the windings 99 and I00 in parallel and through normally closedcontacts GI to a wire I03, through closed contacts B2 to wire 98, and soon as before.

Contactor C operates at once, and contactor D is delayed in itsoperation by a dash-pot or other time-interval device I04. The operationof contactor C closes its contacts CI to C4 and opens the contacts atC5. Upon the operation of contactor C, the winding 35, above referredto, which effects release of the brake, as above described, is nowenergized as follows. The current which flowed to the wire Ii}! flows toa wire I 05 through now closed contacts CI, by a wire I00 through nowclosed contacts C2, to a wire I01, and thence to wire 38, to the winding35, and by wire 39, to a wire I08, through closed contacts C3, by wireI09, through closed contacts C4, and by wire Hi) to wire I03 as before.The winding 35, now receiving current, releases the brake of the press.

At the end of a time interval after the operation of the contactor C,determined by the time interval of the device I04 and which timeinterval is relatively short, the contactor D whose winding is energizedas above described, operates and closes its contacts DI to D4 and thiseffects in a manner which will now be described, energization andoperation of contactors F and M in the order named, the current flowingthrough the contacts C2 as described to the wire I01 and thence throughnow closed contacts DI, closed contacts RI to be referred to, throughthe winding III of contactor F, through now closed contacts D4 andthrough closed contacts B3 to wire I08 and through the closed contactsC3, as before, operating the contactor F, thereby closing controlcontacts F2 and opening control contacts FI, and also closing main motorcurrent contacts F3 and F4 to be referred to.

Current also flows from the wire I01 through closed contacts D2, throughnow closed contacts F2, through the winding I I2 of the contactor M,through closed contacts D3, by a wire II3, through contacts B3 to wireI08, etc, operating contactor M, closing its control contacts MI, andalso the main motor current contacts M2 and M3.

The contactors F and M now being closed, reference may be had to Fig. 6,wherein these contactors are reproduced with the circuits which theirmain contacts control. In this figure, the motor is shown at I0, and ispreferably of the three-phase induction type. Power supply lines areshown at H4, H5 and H6, and current now flows from the main I'I4 throughthe closed contacts M2, and by wire I I! to the motor I0; and currentflows from the line II5 through the contacts M3 and contact F3 and bywire I I8 to the motor; and current flows from the line I I6 through thecontacts F4 and by wire II9 to the motor I0, thus giving current to themotor and starting it and starting the cycle of the press connected tothe motor.

The machine operated limit switches above referred to are, as described,adjustable to open or close at pre-selected points in the cycle ofoperation of the machine, or rotational positions of the shaft 2, andthese are preferably, or as an illustrative instance, set to operate asfollows, and as illustrated diagrammatically in Fig. 7, wherein shadedportions indicate closed condition.

The limit switches 56 and 5'! are set to be closed at the beginning ofthe cycle, and they may be set to open when the main shaft has rotated213 degrees and to close at 828 degrees.

The limit switch 58 is set to be closed at the beginning of the cycleand may be set to open at 213 degrees and close again at 340 degrees.

The limit switches 59 and 60 are set to be open at the beginning of thecycle and may be set to close at degrees and to open at or near the end(beginning) of the cycle.

The limit switch GI is set to be open at the beginning of the cycle andmay be set to close at 45 degrees and open near the end of the cycle,say at 350 degrees.

The purpose of these settings will be explained hereinafter.

Continuing the description, the machine has started its cycle and thehead 5 of the machine is descending. If now, for any reason, one of theoperators, which may be any desired number, each controlling a pair ofpush-buttons 'I--'I, should want to stop the machine or shouldinadvertently remove a hand from a push-button so that he might thenmove his hand or his body into a position of danger, the machine willstop at once, because the control current to the motor contactors F andM, and to the brake winding 35 will thereby be broken and the brake willset and stop the machine.

It is one of the advantages of my invention that this interruption ofcontrol current is effected directly upon the contacts of thepushbuttons such as the contacts 11, as a feature of safety. Forexample, if the control current to the said contactors could only bebroken at the contacts of the contactors B, C and D, and thesecontactors or some of them, should stick closed, as sometimes occurs inpractice with electromagnetic contactors, the press would unexpectedlycontinue to run when the said push-button was opened. In the controlsystem above described, the current to the brake winding 35 and to thewindings of the motor contactors F and M, is initiated through thecontacts of the electro-magnetic contactors B, C and D, after thepush-button contacts IT-11 have been closed, but this control current isbroken directly on the push-button contacts 'I'! if any of thepushbuttons is opened. In practice, the amount of current taken by thebrake-winding 35 and by the windings I II and I I2 of the motorcontactors F and M is relatively large current when initiated, but whenthe brake and the said contactors have operated, the current is greatlyreduced, due to the increased induction thereof effected by closing orpartly closing the magnetic circuits of their electro-magnetic elements,and this reduced current can practicably be broken upon the push-buttoncontacts 11, although for the size and type of push-buttons commonlyemployed in this art, it might be impracticable to initiate the currenton the pushbutton contacts. It follows that the control current whicheifects starting of the motor and beginning of the cycle is initiatedthrough the contacts 11 of the push-buttons after they are closed, butis infallibly interrupted directly upon these contacts to stop thepress, in what may be called the dangerous part of the cycle,

After the press has made a part of the cycle such as 115 degrees, in theillustrative instance referred to, the head 5 of the press has movedsufficiently far down so that danger has passed, and it is desirablethen to free the operators from their push-buttons to enable them to dosome other work at the machine and to take over the control from thepush-buttons '|-'I, the limit switches 59 and 50 are provided, which nowclose.

Upon their closure, control current flows from the wire 93, as beforethrough the closed limit switch 59 and there divides, part flowing bywire I06 through closed contacts CI, wire I55, wire I02, through thewindings of the switches C and D, through contacts GI, wire I I0,contacts C4, wire I09, closed limit switch 60, to wire 95, and so on, asbefore, holding the contactors C and D closed; and the other branch ofthe current flowing from the limit switch 59, through closed contactsC2, to wire I01 and thence as before through the windings 35, I I I andI I2, to the wire I08,-through closed contacts C3, and closed limitswitch 50, to wire 95, and so on.

The machine now continues to operate under this control until the end ofthe cycle is reached, at or near which the limit switches 59 and 60 openagain to interrupt the control current, cutting off the motor current atthe switches F and M, and setting the brake by de-energizing the brakewinding 35, and the press stops.

It will be observed that the limit switches 56 and 5'! opened, at say,213 degrees of the cycle, after the limit switches 59 and 60 had closed,and thereupon th contactor A opened, because its maintaining circuitthrough the limit switches 56 and 51 was opened, and this openedcontacts AI to A4. The contacts AI and A2 prevent the contactor A fromagain closing when the limit switches 58 and 51 again close, say at 328degrees, if the push-button contacts I'I'I'I are maintained closed bythe push-buttons; and the open contacts A3 and A4 prevent the contactorsB, C and D from being held closed after the limit switches 59 and 55 areopen, even if the pushbutton contacts ll-TI are held closed. It followstherefore that even if all of the push-buttons 'I'l are held closedclear to the end of the cycle, the press will nevertheless come to restat the end of the cycle.

On the other hand, if the push buttons I--'I had all been released whenor after the control thereof was taken over by the limit switches 59 and50, and if therefore the push-button contacts IS-15 are closed at theend of the cycle, then the contactor A will remain operated; or if ithad been opened by the limit switches 56 and it will again close as inthe first instance; but the press would nevertheless come to restbecause the control circuit will be broken by the lnnit switches 59 and50.

If, on the other hand, the push-buttons I-'I had been maintained closedto the end of the cycle and the press came to rest, as described, andthe contactor A therefore was open, then before another cycle can beinitiated, the pushbuttons 'I-'l must all be released and close theircontacts I5 to get the contactor A closed and then must all be depressedagain to close the contacts TI to initiate the next cycle.

The necessity of thus releasing all of the pushbuttons to close theircontacts 16-45 before another cycle can be initiated thereby issometimes referred to as an anti-repeat safety feature.

If it be desired that the press shall operate continuously, cycle aftercycle, after once being started, the master controller, Fig. 4, is movedto engage the off contacts With the continuous contacts therebyconnecting contacts 52-63, 64-65, 55-61, 5869, and iii-H, in Fig, 4 andin Fig. 3.

To start the press, the push-buttons |-'I are again depressed to closethe contacts IL-TI to energize the brake winding 35 to release the brakeand to close the motor contactors F and M, contactors B, C and D, F andM, operating in sequence as before. As soon as the contactor M operatesand closes the control contacts MI, control current flows from thesupply mains 89 through the stop push-button 38, controller con tacts5253, Wire 93, controller contacts 655I, closed contacts MI, to wireE96, and there the current divides, one branch flowing through contactsCI to wires I55 and I92, through the windings of th contactors C and D,through closed contacts GI, contacts C4, controller contacts 68-69, wire55, etc.; and the other branch flowing from wire I55, through contactsC2, to wire I51, and thence through the brake winding 35 and thewindings of the contactors F and M, to wire I08 as before, and thencethrough contacts C3, and by wire I09, through contacts 6369, to wire 95.Contactors C and D are thus held closed as are contactors F and M, andthe brake winding 35 is maintained energized so that the press continuesto run and repeat independently of the push-buttons 7--7 and the limitswitches 5850.

To stop the machine the stop push button 83 is operated and any numberof such stop buttons may be provided at any desired locations and anyone of them interrupts the current to the brake winding and to thewindings of the contactors F and M, interrupting the motor current andstopping the machine, and opening all of the contactors, including thecontrol contacts MI. When the stop-button 83 is restored, the controlcircuit for continuous operation is open at the contacts Mi, and themachine does not again start, and must be again started by the operationof the push-buttons I--7, as before, to close the contactor M and itscontacts MI for further continuous operation.

Of course, it will be understood that during run or cycle-by-cycleoperation, as first described, operation of the stop-button 38, bycutting ofi all control current will open all of the contactors and setthe brake.

Suppose now that it be desired to inch the press increment by incrementas referred to, the controller of Fig. 4 is moved to engage the offcontacts with the inch contacts, connecting contacts 70-71, 273, 7G75,in Fig. 4 and in Fig. 3.

To inch the press in the forward direction, the push-button 78 isdepressed, opening contacts IS-80 and closing contacts 8I82. Currentthen flows from the supply main 89 through the stop push-button 88,controller contacts 72-73, by wire I20, closed contacts 84, wire IEI,closed contacts 8!, wire I22, wire I02, through the windings of thecontactors C and D, contacts GI, wire I23, closed contacts 82, wire !25,and contacts 74-75 to wire 90.

Contactors C and D then close in sequence as described, and then currentflows from the wire I22 to wire I05, contacts CI, wire I08, contacts C2,wire I07, through contacts DI, contacts RI, winding of the switch F,contacts D4, wire H3, contacts 70-7I, wire I68, contacts C3, wire 09,contacts C4, wire I ID to wire I23 and so on, closing contactor F; andcurrent also flows from wire I07 through contacts D2, contacts F2,winding of the switch M, contacts D3, contacts 7fi7I, to wire I08, andso on, closing the switch M; and current also flows from wire ifiI,through the brake winding 35 to wire I60 and so on, releas- 511:

ing the brake. Because of the delay of contactor D, the contactors F andM close in the sequence mentioned after the release of the brake.

When the forward inch push-button I8 is released the control circuitjust described is broken and the press stops, and the press, of course,will run by its inching movement as long as the push-button 73 ismaintained depressed.

If, however, it be desired to inch the press in the reverse direction,the push-button 83 is depressed, opening contacts 8485 and closingcontacts 80-07. Current from wire I as before now flows through closedcontacts 73, through closed contacts 86, by wires I28 and 27, throughthe windings I20 and I29 of the contactors G and H, by wire I30 throughclosed cont-acts C5, by wire I3! through closed contacts 87, throughclosed contacts 00 to wir I25, and so on. Contactor G closes andsubsequently thereto contactor H closes, being delayed by atime-interval device such as the dash-pot I32 diagrammaticallyillustrated,

When contactor G closes, it closes contacts G2 and G3 and opens contactsGI and then current flows as before to wire I26, thence through closedcontacts G2 to wire I07, through the brake winding 35 to wire I08,thence through contacts G3 to wire E31, releasing the brake. Whencontactor H closes it closes contacts HI to H4 and the current flowingfrom the wire I20 through contacts G2 to the wire I07, flows througscontacts H2, contacts Fl, winding I33 of the cont-actor R, contacts H3to the wire I08, and through contacts G2 to the wire I07, flows throughcnotacts B, closing its contacts RI and opening its contacts R2. Currentthen flows as before to the wire I07 and thence through contacts HI,contacts R2, winding H2 of the contactor M, contacts H4, by wire I34,through contacts 7I to the wire I02, contacts G3 to wire I3I, and so on,closing contactor M.

This, by reference to Fig, 6, gives current to the motor I0 in thereverse direction, current from the main I M of that figure flowingthrough the contacts M2 of the contactor M to the wire 1 I7, being inthe same direction as before; but the current in the other two phases ofthe motor being reversed, current from the main H5 flowing throughcontacts M3, by a wire I35, through contacts R3, to the main H9, andcurrent from the main IIS flowing by wire I30 through contacts R4 and bywire I37 to the main I I3,

The motor thus inches in the reverse direction so long as thepush-button 83 is held depressed, and the control circuits are brokenwhen it is released and the brake is set to stop the press.

There are a number of interlocks throughout the system by which abnormaloperation is prevented, besides the safety features above described. Thecontactors C and D cannot operate unless the contactor G is open, thisbeing effected by placing the contacts GI in series with the windings ofthe contactors C and D. The contaotors G and H cannot operate unless thecontactor C is open, this being effected by placing the contacts C5 inseries with the windings of the contactors G and H. The usual interlockbetween the forward and reverse contactors F and B is effected by thecontacts RI and FI.

Furthermore, when the inch push-button 78 or 03 are operated, controlcurrent to the brake winding and to the contactors F and M, or R and Mas the case may be, is initiated by magnetic contactors, but the controlcurrent to the brake winding is interrupted directly on the push-buttoncontacts to set the brake, even if a magnetic contactor should stickclosed, this corresponding to a like protection described above at thecontacts 77 of the push-buttons I, and in this connection, it may beadded that the brake may be made powerful enough to stop the press evenif the motor continues to be energized.

As referred to above, by providing the dashpot or other time intervaldevices I04 and I32,

closure of the main motor current contactors F and M, or R and M as thecase may be, to effect starting, is delayed until after the brake isreleased. Provision may also be made, if desired, as will now bedescribed, to insure that the motor current will be interrupted toeffect stopping, before the brake is set, particularly when the machineis operating by single cycles, that is to say, with the controller ofFig. 4 in the run position.

When the operators depress their push-buttons 7-! to cause thecontactors B, C and D to close, and the brake winding 35 and thewindings III and H2 of the contactors F and M to be energized across thewires I07 and I08, the current through the windings of the contactors Fand M flows through closed contacts B3. It will be assumed that theoperators will hold their pushbuttons closed to the end of the cycle.The limit switch 58 is provided and is set to open at about 213 degreesand to close at about 340 degrees; which opening point is after thelimit switches 59 and 60 close to take over the control from thepush-buttons. Opening of the limit switch 58 de-energizes contactor Band causes the said contacts B3 to open, and thereafter the current tothe winding of the contactors F and M flows through a limit switch BI,provided in parallel with the contacts B3, this limit switch being setto close at about 45 degrees from the start of the cycle and opening sayat 350 degrees. When the cycle has proceeded to approximately 350degrees, the limit switch 6| opens and breaks the current to thecontactors F and M (B3 being open) causing them to open to break themotor current, and the momentum of the press will cause it to drift theremaining 10 degrees of the cycle, and open the limit switches 59 and 89to de-energize the brake winding and set the brake. Thus, the motor isde-energized before the brake is set. In the meantime, and at about 340degrees, the limit switch 58 controlling the contactor B has againclosed, so that when the push-buttons "I are released to again operatethe contactor A, and then again depressed, another cycle can berepeated.

In some cases the operators become expert and will release theirpush-buttons I to again operate the contactor A and then depress thepushbuttons for the next cycle, before the press has reached the end ofthe preceding cycle. In this connection, the limit switch 58 is set toclose before the limit switch 6| opens; and contactor B, and thereforecontacts B3 as well as contactors C and D, and their associated contactswill close before limit switch BI opens; so that when the press reachesthe end of the cycle, at say 360 degrees, the limit switches 59 and 60will be ineffective as will also the limit switch BI, and the press maytherefore immediately, and without stopping, proceed on the next cycle.

It is assumed that when the limit switch BI opens at 350 degrees toeffect cutting off of the motor current, that the press will by momentumdrift to the end of the cycle at which the limit switches 59 and 69 opento set the brake, but if, due to any cause, the press should not driftto the end of the cycle, the limit switch 58 will in any event bealready closed at 340 degrees so that if the push-buttons are heldclosed or are again closed, B3 will be closed, bridging the limit switch6|, and the press will continue to the end of the cycle. The provisionfor adjustment of the limit switches-above described makes possible asetting of the limit switch 6| at which, when it cuts oil the motorcurrent, the press will drift to the end of the cycle at which the brakeis set subsequently to the opening of the motor circuit.

In the arrangement described above in connection with Fig. 3, current toenergize the brake winding 35 and the windings of the motor switches Fand M all flows over a line comprising in series the contacts 11 of thepush-buttons, Wire 91, wire IOI, wire I05, wire I96, and wire I01; andafter flowing through the said windings goes back to the source over alike wire circuit; and in some cases the necessary current is so greatat the relatively low voltage, such as 110 volts, which it is desired touse on the mains 89 and 90, that excessively large wires must beemployed in an installation, and in some cases it may be desirable tosacrifice some of the advantages described above for this system forthis reason.

Such a modified system is shown in Fig. 5. In this system, the circuitsfor the push-buttons, contactors A, B, C and D, limit switches 59 and60, controller contacts 62 and 63, 64 and B5, 66 and 61, 68 and 69,12and I3, I4 and "I5, and the operation thereof, down to and including theclosure of contacts C and D, is the same as that described in connectionwith Fig. 3. The system below the contactors C and D is, in general,different, and will be described in connection with a description of itsmode of operation.

When the master controller of Fig. 4 is set for the run position and theoperators have pressed their push-buttons 'I-l, contactors B, C and Dclose as before. Upon the operation of contactor C, and closure of itscontacts CI to C4, current flows directly from the main 89 by a wire I38to a wire I39, thence through closed contacts C2, through the winding 35of the brake, through closed contacts C3, by a wire I49, and a wire MI,to the other supply main 9E3, releasing the brake.

Upon the subsequent operation of contactor D current, which as abovedescribed flows through the contact C2, flows by a wire I42, to a wireI43, and thence through closed contacts DI, and contacts RI, through theWinding I I I of the contactor F, and through contacts DI, and closedcontacts B3, to a Wire M4, and thence through contacts C3, to wires I40,MI, and so on, operating the motor contactor F; and after the contactorF has operated current flows from the wire I63, through closed contactsD2, closed contacts F2,

- through the winding II2 of the contactor M, through contacts D3, andwire I45, through contacts B3, to the wire I44, etc., operating themotor switch M, and the motor starts in the forward direction.

When the contactor C is opened, either by release of the push-button "Iin the early part of the cycle or by operation of the limit switches 59and 69 later in the cycle, the contacts C2 and C3 open, causing themotor current to be out off at the contactors F and M, and setting thebrake, the limit switch BI operating as before to effect the sequencethereof.

When it is desired that the machine shall run continuously, cycle aftercycle, the controller contacts 66 and 61, 68 and 69, and I9 and II willbe closed. The cycle is initiated by closing the push-button I asdescribed above, to effect release of the brake and operation of themotor contactors F and M. As soon as contactor M closes its contact MI,contactors C and D will remain energized, as in the form of Fig. 3, andtheir contacts conduct current from the wire I38 to the wire I4I tomaintain contactors F and M operated and the brake released, asdescribed above for continuous operation of the machine, until thecircuit to the contactors C and D is interrupted by the stop button 88.

If it be desired to inch in the forward direc tion, the controllercontacts 'I'2-'I3, "I li l and Ill-II will be closed and upon depressingthe forward inch button "It, current will flow from the wire I20, asdescribed in connection with Fig. 3, to the wire I92, operatingcontactors C and D, and when the contacts C2 and C3 close, the brake andthe contactors F and M will be operated as before, the limit switch 5|being bridged by the controller contacts 'IIil I, and the motor will runas long as the forward push-button 28 is maintained depressed, subjectas before, to be-- ing stopped by the stop-button 88.

When it is desired to inch in the reverse direction, the reverse inchpush button 83 is depressed, current then flows from the wire in asbefore to a wire I28 and thence by wire I21 through the windings cf thecontactors G and H, to the wire E36, through contacts C5, to wire [3| asbefore, operating the contactors G and H in sequence. Upon operation ofcontactor G, which has one set of normally closed contacts Gi, and foursets of normally open contacts G2 to G5, current flows from the line 89to wire I38 and thence through closed contacts G2, to wire M3, thencethrough the brake winding 35, to wire I44, and through contacts G4, tothe wire Hi, and thence to the line 90, releasing the brake.Subsequently, upon operation of contactor H, current flows from the wire138, through closed contacts G3, contacts H2, contacts Fl, through thewinding of the contactor R, closed contacts H3 and G5, to the wire Ml,etc., operating contactor R; and then current flows from the wire I38,through the contacts G2, Hi, and R2, through the winding of thecontactor M, through contacts H4 to wire MG, through controller contacts'H to wire H27, and through contacts G4 to the wire M8, and so on; andthe brake being released and the contactors M and B being closed, themotor starts and will be stopped when the push-button 83 is released tode-energize the contactors G and H.

It will be apparent from Fig. 5, that the machine and its motor may becaused to operate a single cycle and stop, or repeat the cyclescontinuously, or be inched in either direction, as in the form of Fig.3, but that the brake Winding 35, and the windings of the contactors F,M and R, are energized directly across the supply mains, theenergization being both initiated and interrupted on the contacts ofmagnetic contactors which may be desirable in some cases, as explainedabove.

The push-button switches ':'-l and 88 and l883 are referred to asnormally taking up the positions illustrated and as is well known thismay be eilected by springs or other means not shown, yieldable to permitthe push button to be moved to its operated position and to restore itto its normal position when released.

My invention is not limited to the exact details of constructionillustrated and described, changes and modifications may be made withinthe spirit of my invention without sacrificing its advantages and withinthe scope of the appended claims.

I claim:

1. In a control system for a cyclically operating machine, an electricmotor drivingly connected to the machine, a source of electric current,a normally set brake for stopping and holding the machine, an operatorsswitch, means including electrically operable means and circuit meansassociated therewith responsive to operation of the operators switch toeffect release of the brake and energization of the motor to start themachine and motor, and switch means operable by movement of the machineat the end of a cycle to effect de-energization of the motor and settingof the brake to stop the machine, and means to cause tie-energization ofthe motor to occur before setting of the brake to stop the machine.

2. In a control system for a cyclically operating machine, a source ofelectric current, an electric motor drivingly connected to the machine,a brake for the machine, an operators switch, a

magnetic device and means associated therewith to efiect release of thebrake when energized and setting of the brake when de-energizd, magneticmeans and circuit means associated therewith effective when energized toeffect energization of the device and release of the brake andenergization of the motor by current from the source to start themachine and motor, a circuit controlled by the operators switch forenergizing the magnetic means when the contacts of the operators switchare closed, and for de-energizing the magnetic means and for alsode-energizing the magnetic device directly at the contacts of theoperators switch when it is opened.

3. In a control system for a cyclically operating machine, a source ofelectric current, an electric motor drivingly connected to the machine,a normally set brake for stopping and holding the machine, an operatorsswitch, an electro-magnetic device and means associated therewith toeiiect release of the brake when the device is energized,electro-magnetic means and switch means operated thereby to eiiectenergization of the motor by source current to start it and the machine,the energization of the electro-magnetic means being responsive toclosure of the operators switch, the energization of the device beingresponsive to operation of the switch means by the elec-tro-magneticmeans, and de-energization of the device being responsive directly toopening of the operators switch.

4. In a control system for a cyclically operating machine, a source ofelectric current, an electric motor drivingly connected to the machine,a normally set brake for stopping and holding the machine, an operatorsswitch, an electro-magnetic device and means associated therewith toefiect release of the brake when the device is energized and setting ofthe brake When it is de-energized, electro-magnetic means and circuitmeans associated therewith to effect energization of the motor by sourcecurrent to start it and the machine when the electro-magnetic means isenergized and effect de-energization of the motor when it isde-energized, the energization of the electro-magnetic means and thedevice being responsive successively to closure of the operators switch,de-energization of the device being responsive to operation of theoperators switch.

5. In a control system for a cyclically operating machine, an electricmotor drivingly connected to the machine, a normally get brake forstopping and holding the machine, an operators switch, anelectro-magnetic device and means associated therewith to effect releaseof the brake when the device is energized and setting of the brake whenit is de-energized, electro-magnetic means and circuit means associatedtherewith to effect energization of the motor to start it and themachine when the electro-magnetic means is energized and to effectde-energization of the motor when de-energized, the energization andde-energization of the device and the electromagnetic means beingrespectively respcnsive to operation and restoring of the operatorsswitch, means including delayed operating means to cause release of thebrake to occur before energization of the motor, and a switch operatedby movement of the machine at a predetermined point in its cycle tocause de-energization of the motor to occur before release of the brake.

6. In a control system for a cyclically operating machine, an electricmotor drivingly connected to the machine, a normally set brake forstopping and holding the machine, a normally open operators switch, anelectro-magnetic device and means associated therewith to effect releaseof the brake when the device is energized and setting of the brake whenit is de-energized, electromagnetic means and circuit means associated 5therewith to effect energization of the motor to start it and themachine when the electro-magnetic means is energized and to effectde-energization of the motor when de-energized, means including circuitmeans to cause the energiza- 0 tion and de-energization of the deviceand the electro-magnetic means to be respectively responsive tooperation and restoring of the operators switch, means including circuitmeans to cause the energizing current to the device to flow 15 throughthe operators switch after closing thereof and to cause the current tothe device to be broken directly on the operators switch when opened.

7. In a control system for a cyclically oper- 20 ating machine, anelectric motor drivingly connected to the machine, a normally set brakefor stopping and holding the machine, a normally open operators switch,an electro-magnetic device and means associated therewith to effectrelease of the brake when the device is energized and setting of thebrake when it is ole-energized, electro-magnetic means and circuit meansassociated therewith to efiect energization of the m0- tor to start itand the machine when the electromagnetic means is energized and toeffect deenergization of the motor when de-energized, means includingcircuit means and delayed operation means to cause energization of thedevice to occur before energization of the motor, and means including aswitch operated by movement of the machine at a predetermined point inits cycle to cause de--energization of the device to occur afterde-energization of the motor.

OSWALD M. BUNDY.

